The David Plant Collection, J.A.P V-twin Veteran Re-creation Project

Registration no. not registered
Frame no. none
Engine no. 4382

"In The Motor Cycle reports of the 1905 Stanley Show there is no mention of a JAP exhibit, although a new 6hp vee-twin engine was observed fitted to a BAT machine... In point of fact, the vee-twin was not the first of its kind to leave the works at Tottenham. The first 70x95mm 6hp engine had been made in 1904, and like the water-cooled version that followed it, it had automatic inlet valves. An early photograph in the Tottenham Museum archives shows the air-cooled version fitted into a JAP motorcycle in 1905." - Jeff Clew, JAP The Vintage Years.

For many years the dominant supplier of engines to the British motorcycle industry, JAP was founded by John Alfred Prestwich in the closing decade of the 19th Century. JAP's arrival on the scene reduced British manufacturers' reliance on Continental power units, but at first the London-based company specialised in the production of scientific instruments, John Prestwich collaborating with William Friese-Green in pioneering the development of the ciné camera, before building its first motorcycle engine around 1901. In production from 1903, JAP's first engine, a 2½hp four-stroke single featuring 'atmospheric' inlet and side exhaust valves, displaced 293cc (76x70mm bore and stroke) and produced a claimed 2.25bhp at 1,600rpm. As well as supplying existing manufacturers, JAP went into motorcycle production itself, though from 1908 the firm concentrated on engine supply alone. JAP was active in competitions right from the start, entering the ACU's 1,000-Mile Trial in 1903 and supplying the engine for Charlie Collier's winning Matchless in the inaugural Isle of Man TT of 1908.

This fascinating JAP project started with the basic v-twin engine, David says this may have come from the same source as the early Matchless in his collection but cannot remember. The idea was to create a JAP motorcycle of the 1904-1905 era using a photograph in a book but with variations as dictated by the components available, at no point to be an authentic copy. The frame is all new as are the engine mounts; the bottom bracket and its components; front fork bracing and yokes; inlet manifold; control levers and mountings; pedal cranks; mudguards (packed separately); exhaust box, etc. All the above were scratch built with some artistic licence. The engine is loosely assembled, the pistons, crankshaft and connecting rods being packed separately. The engine has received little attention apart from the provision of an ignition pack plate. The rear hub is new-old-stock BSA with a back pedalling brake, modified with larger spoke flanges. The front hub is believed new, again scratch built. A rear hub has now been obtained (since the catalogue photography was completed). A potentially most rewarding project.

Condition and completeness unknown, Prospective purchasers should satisfy themselves with regard to this motorcycle's completeness, history, authenticity, originality and mechanical condition prior to bidding.